Drainage pump systems are used to aspirate body liquids and fluids in the medical field, for example after surgical interventions, but also in wound drainage, in thorax drainage or in liposuction. These drainage pump systems usually have a suction pump, one or more fluid collection containers, and a drainage tube connection between a patient and fluid collection container. The fluid collection container can be secured releasably on the housing of the drainage pump or can be connected to the pump via a vacuum tube.
With an underpressure being generated in the fluid collection container by means of the suction pump or vacuum pump, the fluid or secretions from a cavity in the patient can be aspirated through the drainage tube into the collection container and collected therein. Filters arranged on the pump-side outlet of the collection container protect the suction pump from possible contamination by the aspirated fluid.
In addition to the drainage line, it is also known to run a service line from the pump to the patient, for example as a measurement line for determining flow differences and pressure differences or for delivering air or gas in order to flush the cavity. Examples of this are disclosed in U.S. Pat. Nos. 5,738,656 and 5,134,996, both of which disclose double-lumen or multi-lumen tubes.
Such measurements of changes in pressure are important aids to physicians and nursing personnel. Changes in pressure during the aspiration provide indications, for example, as to the functionality of the suction pump, the leaktightness of the tube connections, and the healing process.
Moreover, WO 2008/141470 discloses a drainage tube unit for aspirating body fluids by means of a suction pump. The tube unit comprises a pump-side attachment part, a patient-side attachment part, a drainage tube and at least one service tube. The service tube can be used for the abovementioned actions. The tubes are held with a first end in the patient-side attachment part and with a second end in the pump-side attachment part. The ends of the tubes in the patient-side attachment part are held separate from each other in the respective attachment parts and are connected to each other via a connection channel. The drainage tube unit can be produced inexpensively and is easy to use and reliable.
It is also known to use hydrophobic filters in order to avoid contamination of the suction pump. For example, U.S. Pat. No. 4,731,260 discloses a fluid container with a cylindrical filter insert. U.S. Pat. No. 4,636,313 discloses a coupling part of a drainage tube with an integrated bacterial filter.
Devices for removing gases from liquids are also known which use gas-permeable and liquid-impermeable filters. As the liquid flows through these filters, the filters take up the liquid to a certain degree and thereafter do not allow the rest of the liquid to pass through. Examples of these are WO 2005/035033, U.S. Pat. Nos. 3,631,654 and 4,031,891.